Bobby Valentine grudgingly tipped his cap to one of the best pitching performances anybody had thrown at his Mets all season. And Atlanta manager Bobby Cox called it the best-pitched game he had seen all year, for or against his Braves.

The author of this gem? The pitcher that had turned the Mets’ bats into so much dead wood? Not four-time Cy Young winner Greg Maddux. Not two-time winner Tom Glavine, or even 1996 winner John Smoltz.

No, this was 24-year-old Kevin Millwood who smothered the Mets 3-0 in front of a hot and hostile crowd of 43,256 at sweaty Shea Stadium yesterday. It’s been the oft-overlooked Millwood who has emerged as the fourth ace in Atlanta’s hand, notching his team-high 10th win and pitching the NL East-leading Braves to their third straight shutout of the second-place Mets.

“We’re battling these guys for first place. When you go out and play the next closest team, the team you’re battling, you’re gonna be a little more intense than normal,” Millwood said. “I was pretty excited to get a chance to pitch against them. We’ve been playing pretty well lately, [and] I thought if I could go out there and keep them to a few runs, we’d have a good chance to win.”

He did one better than that; he kept them to no runs. Millwood – who began the season just 1-2 with a fat 5.79 ERA, but since shortening his stride in April, he’s gone 9-2 in his last 14 starts with a sterling 2.90 ERA – threw eight-plus shutout innings, fanning six and not allowing a single runner past first base.

“He made terrific pitches. When you’re a pro, you learn to tip your hat, as reluctantly as [you do it],” Valentine said. “But you’ve got to tip your hat to him. I’m not sure I knew he could sustain that for eight innings, but he could.”

And the praise was no less ebullient from the other clubhouse.

“It was a great, great performance. It was smoking out there, but so was Kevin,” pitching coach Leo Mazzone said of Millwood, who got by with just a fastball and nasty slider, and never really needed his curve or changeup. He threw 112 pitches in 85 degree heat that felt like 95, surrendering only harmless singles to Robin Ventura in the fifth and John Olerud in the seventh.